Info about Wines

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A considerable proportion of wines that are exhibited in competitions often reveal

A considerable proportion of wines that are exhibited in competitions often reveal "off-characters". Those "off-characters" mostly are due to winemaker's inexperience in the art of wine production, negligence, opting for shortcuts, and sometimes owing to aspects that are not under the winemaker's control. Thus, a wine which has extremely high or extremely low acid content, incorrect sweetness proportion, or is considered as undrinkable because of strong presence of tannin, is considered to have faults and flaws. Wine faults and flaws are normally divided into two separate groups. First group includes wines those have flaws owing to mistakes in winemaking process or improper storage management and the second group consists of wines which have faults due to
unavoidable conditions.


• Chloroanisoles and bromoanisoles


Wine contagion with fungal scents is widely acknowledged as the most terrible hazard for the wine cellars all across the globe. This occurrence is commonly known as wine contamination or “cork taint” and is mainly attributable to the cork stopper or wine cellar. Wine contamination is caused by chemical compounds commonly known as chloroanisoles and bromoanisoles which produce the fungal scents in the wines and also tend to change the wine flavor.


• Fermentation in the bottle and bacterial spoilage


Different types of bacteria are found to grow on grapes as well as in grape juice. The most common of the acetic acid bacteria that grow on grapes is known as Gluconobacter oxydans. The moment alcoholic fermentation begins the growth and development of acetic acid bacteria tends to decrease significantly. But when alcoholic fermentation is delayed the production of CO2 begins to reduce, making oxygen easily available, which may help in the growth of acetic acid bacteria in the wine once again and accelerate the production of acetic acid.


• Protein haze


Gradual protein denaturation in wines is widely believed to cause protein formation, as well as formation of a hazy suspension along with precipitates. The most common wine proteins that are accountable for formation of haze are derived from grapes. They usually contain low molecular weight as well as isoelectric points. Addition of protein haze defending things like yeast mannoproteins, to wines can reduce the size of the haze particles.


• Oxidation


Wine oxidation has fairly dissimilar effects for white and red wine varieties, even though the fundamental chemistry is related. Additions of oxygen are generally necessary for the maturation process of red wines previous to bottling, in order to improve the wine quality by means of elimination of surplus aromas, to balance color as well as to increase the taste. Conversely, addition of oxygen rarely enhances the quality of white wines where upholding of fruity scents is required, and moreover, oxidative browning usually spoil the wine appearance.


• Excessive volatile acidity


Wines which contain excessive volatile acidity are normally regarded as detrimental owing to their sour, pungent flavor. Even though bad grape harvests are capable of producing wine with excessive volatile acidity levels, but the actual problem surfaces during the fermentation process. Some bacteria present within wine are capable of generating a surplus of acid in the course of the maturing process. Microbes that help in alcohol metabolism and change it into acetic acid are considered as the chief donors to volatile acidity.


• Excessive sulfur dioxide


The presence of excessive sulfur dioxide in wine can destroy the good yeast, and can hinder the fermentation process and can even hamper malolactic fermentation before it can reach the final stage. Wines that contain excessive sulfur dioxide usually have a pungent smell which is quite similar to the smell of a recently burnt matchstick. Sulfur dioxide when combines with anthocyanins (which provide the red color to the red wines) tends to make them inactive. This results in red wines to loose their characteristic properties and color.


• Reductivity


Wine reductivity is quite similar to the oxidation? process. Both tend to change the natural appearance of the wine. Excess reductivity can hamper a wine's flavors and aromas. While oxidation progressively changes wine into a musty, caramel-like quality, reductivity on the other hand constantly forces further destructive sulphurous quality into wine giving it a smell of a recently struck matchstick or of rotten eggs. Wine reductivity revolves around hydrogen sulphide compounds which are produced by yeast, in the course of fermentation, due to lack of oxygen.


• Brettanomyces


Brettanomyces falls in the family of yeasts and grows on the skin of the grape fruit. When Brettanomyces breeds in wine it generates numerous compounds, which can change the taste and appearance. At depleted levels a number of winemakers believe that the existence of such compounds usually have an optimistic consequence on wine, adding to intricacy, and also provids an aged appeal to certain young red wines.


• Dekkera


Dekkera can prove to be a powerful destructive organism especially in wines. These types of yeasts generate high amount of phenolic compounds, and volatile acids. Among all the phenolic compounds the ethyl phenols are considered to be the most important. At low intensity these phenolic compounds can increase wine intricacy, whereas at elevated levels it is considered as wine spoilage. They usually tend to change the appearance of the wine from sparkling to a musty look.


• Geraniol


Geraniol is an alcohol and a monoterpenoid. Geraniol is the normally found in palmarosa oil, citronella oil and rose oil. It is also found in little quantities in lemon, and geranium. It looks like a transparent to pale-yellowish oil that cannot dissolve in water, but can dissolve in ordinary organic solvents. It is mostly used in making perfumes. The presence of geraniol can contaminate wine if the bacteria are permitted to form in the wine.


• Geosmin


The presence of geosmin usually produces an earthy or musty smell in wines. Geosmin is a familiar, extremely scented compound, which has lately been found and measured in white as well as red wines, and in grape juice prior to the process of alcoholic fermentation. In grape juices attained from decayed grapes as well as in wines, geosmin can be discovered at very high concentrations.


• Ethyl acetate


Ethyl acetate is a familiar ester compound in wine. It is produced by ethyl alcohol and acetic acid in the course of the fermentation process. The smell of ethyl acetate is very clear in younger wines. It generally plays a role in providing the fruity flavor in the wine. Too much concentration of ethyl acetate in wine is judged as a wine fault. Oxygen exposure can aggravate the wine fault because of the oxidation process which results in a severe vinegar like taste.


• Excessive acetaldehyde


At scarcely noticeable levels acetaldehyde might add to complexity but it fails to make wine tasting an enjoyable experience and is commonly regarded as a flaw. If excessive acetaldehyde is noticeable then it is considered as a fault and it makes wine undrinkable. The word „oxidation? should not be used to indicate the occurrence of acetaldehyde because it indicates other various components.


• Candida acetaldehyde


At any stage the presence of Candida-acetaldehyde in wine is regarded as a fault.For the majority people a wine which contains Candida-acetaldehyde is considered as undinkable. Such wines usually scores less than 10 points. It gives wine a characteristic, sherry-like, straw-like, "dirty", pungent taste and smell.


• Smoke taint


Smoke tainted smells have been commonly depicted as smell of burn toast, phenolic and burnt bacon and are not at all pleasing. When smoke produced by bush fires are straight away absorbed by the grape vines and the fruits, then the vegetation of a particular wine state tend to leave its mark on the grapes as well as on the wine made from those grapes.